The present invention relates to an expansion method for a radio network having communication terminals and a relay terminal and a support method therefore, and also relates to the communication terminals and the relay terminal.
To extend the communication range of a radio network, a presently available method requires that a relay terminal be positioned between a communication terminal and a base station. But generally, when this method is employed, a radio wave status survey must be performed in advance, to ensure that the relay terminal is properly positioned and that a desired communication quality is obtained. According to another method, however, the performance of a preparatory radio wave status survey is not required. With this method, in order to determine the location of a relay terminal that relays a communication terminal and a base station, an adjustment signal is transmitted by the base station (see, e.g., Japanese Laid Open Patent Publication No. 2000-4469).